Begin by preheating your oven to 350°F (175°C). Grease and flour a 9-inch round cake pan, then line with parchment paper.

In a medium mixing bowl, combine cherries, ⅓ cup sugar, and corn starch. Toss until coated and spread evenly across the cake pan.

In a large mixing bowl, combine sugar, flour, cocoa powder, baking powder, baking soda, salt, eggs, soured milk, brewed coffee, vegetable oil, and vanilla extract. Beat on medium speed until smooth.

Pour cake batter over the cherry mixture evenly, ensuring balance.

Bake for 30-35 minutes until a toothpick comes out clean. Watch for the top to rise and develop a sheen.

Let the cake cool for 5 minutes before inverting onto a serving plate.

Serve warm or allow to cool. Optionally, serve with ice cream or whipped cream.